The present invention relates to a process for coating powder particle substrates, the coated powder particle substrates and to applications and uses thereof. More particularly, the invention relates to coating powder particle substrates with a metal non-oxide-containing material, such material preferably being an electrically and/or thermally conductive non-oxide-containing material and such coated powder substrates.
In many applications using powder it would be advantageous to have an electrically and/or thermally conductive; radiation absorbing and/or anti friction metal non-oxide coatings which are substantially uniform, have high and/or designed conductivity and/or radiation absorbing properties and have good chemical properties, e.g., morphology, stability, corrosion resistance, etc.
A number of techniques have been employed to provide certain metal non-oxide coatings on fixed generally larger size substrates. For example, the CVD processes are well known in the art for coating a single flat surface, which is maintained in a fixed position during the contacting step. The conventional CVD process is an example of a “line-of-sight” process or a “two dimensional” process in which the metal non-oxide is formed only on that portion of the substrate directly in the path of the metal source as metal non-oxide is formed on the substrate. Portions of the substrate, particularly internal and external surfaces, which are shielded from the metal non-oxide being formed, e.g., such as the opposite side and edges of the substrate which extend inwardly from the external surface and substrate layers which are internal or at least partially shielded from the depositing metal non-oxide source by one or more other layers or surfaces closer to the external substrate surface being coated, do not get uniformly coated, if at all, in a “line-of-sight” process. Such shielded substrate portions either are not being contacted by the metal source during line-of-sight processing or are being contacted, if at all, not uniformly by the metal source during line-of-sight processing. A particular problem with “line-of-sight” processes is the need to maintain a fixed distance between the source and the substrate. Otherwise, metal non-oxide can be deposited or formed off the substrate and lost, with a corresponding loss in process and reagent efficiency.
There has been a need to develop processes for producing metal non-oxide coated powder substrate particles and processes, particularly under fast reaction processing conditions, which provide short processing times required for producing high quantities of metal non-oxide coated powder particle substrates and to produce unique metal non-oxide coated powder substrates having improved properties.